Yes, they are still used on older workboats. There are still lots of 2-71 gensets out there. The mains on commercial boats are being replaced because they do not meet pollution standards being two-strokes.

I like the sound of the old 6-71's...brings back memories of being in Seascouts.

In the eighties I built a 63-foot staysail schooner. Used a four valve 6-71 for main power. Pushed it nearly to hull speed with power to spare. It also ran the refrigeration for two cold holds plus all the hydraulics, etc.

While they are a two-stroke don’t compare a two-stroke diesel to a two-stroke gas. The blower on a Jimmy completely exhausts the combustion chamber on each stroke. They accelerate rapidly and while they don’t have the longevity of the older Cats or Cummings they would go for 10,000 hours or so.

The big issue was the fuel economy and it stinks! They tend to suck fuel when pulling a load. I remember a couple of fireboats at Long Beach in the 90’s that had 12V-92’s for propulsion and main pumps, so ran three total. Would hate to buy the fuel!

Ran some 12V’s on gensets on a job once but they used much more fuel than the Cat D277's.

Other than fuel, they start easily and run very smoothly if the rack is set correctly. There is no injector pump on a Detroit but each individual injector must be timed.

Yes, at 1800(full governed rpm) you can hear the blower. Sound as if they are ready to self-destruct because they are firing every rev.

One advantage to the two stroke series is that they can run either clockwise or counter-clockwise with different starters and change the oil pump gears around. That made it easy to have opposite port and starboard prop rotation.

Ah yes , the detroit diesel, trucking co loved them for the fuel savings. Drivers didn't because of the narrow power range (lots of shifting) and then there was the noise, nickname "the screamin gm-ee".

Drove a 65 foot power boat from San Diego to Cabo, PV and Mazatlan and return on several trips that had twin 8V-71's. Reasonably good fuel economy, a little noisy and they must be run up over 1600 rpm every day or so for at least 45 minutes or the turbos begin to plug. Cleaning the blowers is expensive and messy. You'll know when you have stuffed them by the black smoke coming out the exhaust covering the transom! Well cared for they should last many 1000's of hours. On larger installations it helps to have a smaller day tank to draw fuel from as they have a fairly high fuel return rate to keep the injector system cool. Good engines IMHO... Capt Phil